title: Hypophosphatemia during continuous hemodialysis is associated with prolonged respiratory failure in patients with acute kidney injury.
abstract: BACKGROUND
  Hypophosphatemia is common in critically ill patients and has been associated with generalized muscle weakness, ventilatory failure and myocardial dysfunction. Continuous renal replacement therapy causes phosphate depletion, particularly with prolonged and intensive therapy. In a prospective observational cohort of critically ill patients with acute kidney injury (AKI), we examined the incidence of hypophosphatemia during dialysis, associated risk factors and its relationship with prolonged respiratory failure and 28-day mortality.
  
  
  METHODS
  This is a single-center prospective observational study. Included in the study were 321 patients with AKI on continuous dialysis as initial treatment modality.
  
  
  RESULTS
  Four per cent of the patients had a phosphate level <2 mg/dL at initiation and 27% during dialysis. Low baseline phosphate was associated with older age, female gender, parenteral nutrition, vasopressor support, low calcium, and high urea, bilirubin and creatinine, whereas hypophosphatemia during dialysis correlated with the ischemic acute tubular necrosis etiology of renal failure, intensive dose and longer therapy. Serum phosphate decline during dialysis was associated with higher incidence of prolonged respiratory failure requiring tracheostomy [odds ratio (OR) = 1.81; 95% confidence interval (CI) = 1.07-3.08], but not 28-day mortality (OR = 1.16; 95% CI = 0.76-1.77) in multivariable analysis.
  
  
  CONCLUSIONS
  Hypophosphatemia occurs frequently during dialysis, particularly with long and intensive treatment. Decline in serum phosphate levels during dialysis is associated with higher incidence of prolonged respiratory failure requiring tracheostomy, but not 28-day mortality.
authors.affiliation: Department of Nephrology and Hypertension, Cleveland Clinic, Cleveland, OH, USA. demirjs@ccf.org
authors.forename: Sevag
authors.initials: S
authors.lastname: Demirjian
authors.forename: Boon Wee
authors.initials: BW
authors.lastname: Teo
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Guzman
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Heyka
authors.forename: Emil P
authors.initials: EP
authors.lastname: Paganini
authors.forename: William H
authors.initials: WH
authors.lastname: Fissell
authors.forename: Jesse D
authors.initials: JD
authors.lastname: Schold
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schreiber
mesh_terms: D058186:Acute Kidney Injury / Q000150:complications* / Q000401:mortality; D003404:Creatinine / Q000097:blood; D016638:Critical Illness / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D017674:Hypophosphatemia / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D012131:Respiratory Insufficiency / Q000209:etiology* / Q000401:mortality* / Q000601:surgery; D012307:Risk Factors; D015996:Survival Rate; D014139:Tracheostomy; D016896:Treatment Outcome
chemical_list: D003404:Creatinine